Brake adjustment device for nonreturn linkages



Dec. 8, i964 J. E. J. FEULLLY 3,]50242 mam DEvcE FOR NoN-RETURN LINKGESFiled Sept. 7, 1962 van United States Patent O 3,169,242 BRAKEADJUSTMENT DEVHE EUR NGN- RETURN LHNKAGES Jules Emile lloseph Feuiiiy,Paris, France, assigner to Societe Generatie isothermos, Paris, FranceFiled Sept. 7, 1962, Ser. No. 222,t89 Claims priori application France,Mar. 6, 1962,

7 cintas. (ci. iss-aes) This invention relates to control devices whichare adapted for being interposed between double-acting brake i adjustersand linkage systems for brake shoes.

Certain automatic double-acting brake adjusters that are designed toadjust the stroke of the brake shoes operate by an elongation or ashortening of the stroke of the power piston required to apply saidshoes. The automatic elongation or shortening of devices of this type isusually tripped or arrested, respectively when the stroke of the brakeshoes is not correct, and under such conditions both operations areeffected by a control means connected to the brake linkage system.

When a definite relationship exists between the position of the brakelinkage and that of said control means, it is essential that when thebrake is released, said linkage returns all the Way to an initialinoperative position if the adjuster is to work properly.

A linkage system of this type is accordingly associated with a returnspring of adequate strength to return the linkage system to its initialposition. On the other hand, the presence of such a spring has thedisadvantage that it absorbs, in detrimental fashion, a certain fractionof the braking force exerted when applying the brakes. For this reason,certain railway authorities have required that such a spring bedispensed with, notwithstanding the disadvantage incurred of slightfriction of the brake shoes against the steel rims of the wheels undercertain running conditions and especially just after the brakes havebeen released.

The elimination of this spring makes it compulsory to use special brakelinkage adjusters, which do not usually function perfectly.

This invention has for an object to provide means whereby ordinaryadjusters can be used with linkages of the type referred lto while atthe same time ensuring that such normal adjusters operatesatisfactorily.

To this end, this invention relates to a junction device between anadjuster and an associated'linkage member, said device embodying asubstantially endwise lost motion device the magnitude of which lostmotion is equal to the travel of the attachment point on the linkagewhen the latter is moved through an amplitude equal to the distancebetween lthe position of said point when the brake shoes are appliedwithout pressure and the brake actuator is fully retracted and theposition of that same point when the brake actuator is retracted andsaid linkage has returned to the fully-released position, namely tto theposition wherein said brake shoes are spaced from the wheel rims.

ln the case of a reversible-screw-type automatic adjuster, said junctiondevice provides a substantially axial free motion and comprises meansfor preventing any relative rotation between the attachment point of theadjuster and a nut, of said adjuster.

In this way, vehicles that are'prone to the drawback mentionedprecedingly can be equipped with conventional adjusters embodyingabsolute functional corrective means.

The description which follows with reference to the accompanyingdrawing, led by way of example only and not of limitation, will give aclear understanding of how the invention may be carried into practice.

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Referring to the drawing filed herewith:

FG. l is a diagrammatic illustration of the braking system on a vehicleprovided with two pairs of axles, the system being represented with thelinkage in a fully retracted position of release.

HG. 2 shows a similar linkage in the position of application of thebrakes.

FG. 3 illustrates the configuration of the linkage when the brakes arereleased, but showing said linkage in a partly retracted position.

FIG. 4 is a fragmentary sectional view on an enlarged scale of theattachment of said adjuster to a brake linklage component.

FIG. 5 is a sectional view on an enlarged scale taken along the linesV--V of FIG. 4.

The embodiment illustrated by way of example relates to a brake linkagesystem for a vehicle having two pairs `of axles 1, 2, 3 and 4, and .thissystem is actuated by a brake cylinder 5 in which slides a piston 6 ttedwith a hollow rod '7. The power stroke of said piston is made against aresisting spring 3 which is supported in the cylinder 5 disposed aboutsaid hollow rod 7. The latter contains a thrust link 9 pivotallyconnected at 10 to a main braking lever 11, which lever is pivotallyconnected at one of its extremities to a fixed point 12, the `otherextremity being pivotally connected at 13 to a braking draw-link 14.

The other extremity of draw-link 14 is pivotally connected at 15 to oneextremity of a rocker 16, the other extremity of which is pivotallyconnected at 17 to one extremity of a draw-link 18, the other extremityof which is in turn pivotally connected at 19 to a brake shoe rocker 2b.On its end remote from hinge-point 19, said rocker 2t) is provided witha pivotal connection 21 for supporting a brake shoe 22, which brake shoeis adapted to bear against an associated wheel on axle 4. Anintermediate draw-link 23 has one of its ends pivotally connected tto anintermediate point 24 on rocker 20. The other extremity of draw-link 23is pivotally connected at 25 to a link 26, one end of which link swingsabout a stationary point 27, while the other extremity is pivotallyconnected at 28 to a brake shoe 29 associated to one of the wheelsmounted on axle 3.

Rocker 16 has a fulcrum support at 30 by being connected to the clevis31 of a reversible screw linkage adjuster 32, and the operating sleeve33 of said adjuster is provided with an adjusting crank 34 hinged to atilter 35 which pivots about the fulcrum support 30, said tilter beingshaped like a bell-crank, the free end of which cooperates through a pin36 with a slide 37 terminating in a hook means 38.

Said slide 37 is connected by a pin 39 to a compression spring 4t) whichis in turn connected to fulcrum 30. Said slide is pivotally connected at41 to a link 42, one end of which swings about a stationary point 43while the other extremity is pivotally connected at 44 to a draw-link45. Draw-link 45 is connected in turn at pivot 46 to rocker 16, saidpivot 46 being located between connection point 17 and connection point30.

The terminal eye 47 of adjuster screw 32 is connected to a stub axle 48positioned intermediately on a rocker 49 one extremity of which ispivotally connected to a xed point 5t) and the other extremity pivotallyconnected at 51 to the end of a draw-link 52. The draw-link S2 ispivotally connected at 53 to a rocker 54 the other exf tremity of whichis in turn pivotally connected at 55 to a brake-shoe 56 adapted to beapplied against a wheel mounted on axle 1. Said rocker 54 is connectedat pivot 57 to one end of an intermediate draw-link 5S the other end ofwhich is pivotally connected at 59 to a link 60. One extremity 0f saidlink 60 swings about a stationary point 61 while the other extremity ispivotally connected a, targa/is greater simplicity on the drawing, toone side only of the vehicle.

Between the screw 32 and the eye 47 is interposed a slide 64 whichintroduces a degree of axial freedom between said screw and said eye butprevents any relative rotation therebetween.

As is more clearly shown in FIGS. 4 and 5the screw V32, the thread ofwhich is so inclined that the adjuster nut cooperating therewith is ableto reversibly rotate, when free, in response to axially-exerted forces,comprises a cylindrical endV section 65 having two at portions 66.v

Said section 65 is provided with a cylindrical head 67 and the section65 and head 67 are freely slidable in a blind socket 68 attached to eye47. Through the socket 68 are provided two keyways 69, which keywaysreceive without endwise play a fork-shaped key 70 the prongs of whichare inserted free of play in said keyways and straddle said flatportions 66 to permit sliding thereof. A pin71 is adapted tointerconnect the outer ends of the two prongs beneath socket 68. v

Flush with the head 67, when the same is applied against key 7i), saidblind socket 68 is provided with a diametrical perforation 72 adapted toreceive a locking pin.

The device hereinbefore described operates as follows:

In the position shown in FIG. l which corresponds to a fully releasedposition of the brakes, the entire linkage pin 39 further apart therebypressing pin 36 into hook 38. Y

Adjuster crank 34, as the result of the engagement of pin 36 and hook 38Vand the corresponding motion of tilter and hence of adjuster sleeve 33,is in a position such that the adjuster nut is free.

lf a fluid under pressure is now admited into cylinder 5, the resultingswing of link 11 will cause a pull to be,

exerted on draw-link 14 and, through the medium support 30, on theadjuster.

As brake shoes 22 and 29 are applied against the rims of the wheels,hinge-point 17 becomes substantially stationary (neglecting elasticmotion), while in the control system for sleeve 33, slide 37 moves overa shorter path than support 30, so that pin 36 separates from hook 38.Assuming the brake shoe clearances to be correct, sleeve 33 will thenimmobilize the adjuster nut and thereby cause clevis 31 to be rigidlyconnected to screw 32. The spring 40 will be compressed. Y

Since in junction 64, in the position occupied by the linkagecomponents'shown in FIG. 1, head 67 is .applied against key 70, motionof rocker 16 will be transmitted via the hinge-point 48, the rigidadjuster 32. and the nonextensible junction 64, to the link 49, whichlink, more specifically through the medium of draw-link 52, will causebrake shoes 56 and 63 to be applied.

In the course of these various motions, crank 34 moves into the adjusterlocking position shown in FIG. 2. This likewise applies to all the othercomponents of the control system, of the brake linkage and of the brakeactu- 1to1', the hollow rod 7 of which actuator projects out of zylinder5. Y

Should the brake shoe clearances not be correct, the adjusterhereinbefore described would operate in conven- :ional manner, either toprovide an elongation (clearances :oo small), or to provide an initialshortening (clearances too big), provided that said shortening motiontake place during travel of the brakes in the sense of applicationthereof.

When the compressed fluid escapes from cylinder 5, spring 8 has astrength just sutlicient to return link 11, draw-link 14 and rocker 16to the positions shown in FIG. 3. Similarly, spring 4t), the strength ofwhich is restricted to a small fraction e.g. 4% of that developed bypiston 6, is just suflicient to provide the mutual motion betweensupport 3u and slide 37 and to cause crank 34 of adjuster sleeve 33 torevert into the angular freeing sector of the nut associated to saidadjuster. From this motion may be obtained a shortening of said adjusterin case of Vexcessive brake-shoe clearances, provided that theshortening'be obtained when the brakes are released (like- I wise inconventional manner).

Since no other elastic actionl is involved, the adjuster, thrust uponthrough support 3i),A is moved nearer to link i9 through the degree ofplay provided in junction 64. In response to this motion, the terminalcylindrical section of screw 32 slides Without rotation along its flatportions 66 between the prongs of key 70, the Vhead 67 penetrating intosocket 68, whereby the brake linkage system assumes the position shownin FIG. 3, wherein the brake shoes remain substantially in contact withthe Wheel rims but without exerting pressure against the same or causingthem to be substantially restrained.

Under favorable conditions, the jolting caused by travel of the vehiclemay return the brake shoes 4into a position spaced from the wheels. Whenthis is the case, the systern as a whole reverts to the positions shownin FIG. 1. When the opposite is the case, the extensibility of theadjuster will become effective only after the head 67 has returned intoabutment behind key 70.

Thus it may be seen that when the system reverts to the position whereinthe brakes are released, piston 6 and its rod 7 are alone to returnunder the action of spring S. Spring d@ returns rocker i6 and theadjuster to their initial positions. Link 49 and the brake shoe linkagesremain stationary and the head 67 moves through the clearance leftbetween key 70 and the bottom of socket 68.

As the successive brake applications and releases take place, crank 34moves from a locking position (FIG. 2) to an Vunlocking position (FIGS.l and 3) in regard to the adjuster nut.y Should the locking position beclose to the unlocking position reached by the linkage components andshown in FIGS. 1 and 3, locking of said adjuster is obtained in definitefashion with a small expenditure of energy even if no return motionwhatsoever of the linkage takes place at the point where the brake shoesare located.

With an arrangement as hereinbefore described, such non-returned linkagesystem can ,therefore be adjusted by means of a conventional reversibleadjuster whose operation is known'to be particularly reliable.

The arrangement described hereinabove can be supplemented with advantageby mount-ing a tubular member 73, which forms an extension of socket 68,slidably and rotatably overa core member that can act as the adjusternut if necessary, thereby providing advantageous complementary rigidityto the whole assembly as well as providing protection for the screwagainst the introduction of extraneous matter. vSuch rigidity isdesirable in order to avoid undue gravity flexing of said adjuster inthe inoperative position or as the result of inertia effects due tojolting during travel of the vehicle.

Normal opera-tion of such an adjuster remains unaf fected either duringscrewing in or screwing out of the device, due to the angularly rigidconnection existing between the eye 47 and the extremity 65 of screw 32.

When it is desired to replace a brake shoe, a locking pin is insertedinto-the diametrical perforation 72 so' as to'obtaiu, if necessarymanual assistance when releasing the brake, the maximum spacing betweenthe wheel'rms and the brake shoes to be replaced, which spacing will bearcanes obtained simultaneously on all the brake shoes when the linkagesystem is operated to that end.

While the present invention applies more particularly to railwayvehicles and to brake shoes applied against Wheel rims, the invention isby no means limited to such cases but extends also to the braking ofvehicles of ditferent types which make use of braking means other thanshoes and which are adapted to co-operate with drums, discs or likemembers.

While there has been described and illustrated, the presently preferredembodiment of the brake adjuster of this invention, it will beunderstood by those skilled in the art that many modifications orsubstitutions of parts may be made Without departing from the scope ofthe invention.

What l claim is:

i. In a braking device for a vehicle having wheels, the provision ofbraking means for being applied against said wheels, brake actuationmeans for operating said braking means and having extended and retractedpositions for respectively applying the braking means against the Wheelsand releasing the braking means, linkage means etween said brakeactuation means and Said braking means and having a fully releasedrelaxed position in which the braking means is spaced from the wheels,linkage adjuster means connected to the linkage means for adjusting theclearance between the braking means and the wheels during operation whenthe linkage means is in a relaxed position and the braking means is justin contact With the Wheels and means connected to said adjuster meansand the linkage means for providing lost motion between said adjustermeans and the linkage means to enable the linkage means to remain inrelaxed position as the linkage means moves to the fully releasedposition in which the braking means is properly spaced from the wheels,said linkage adjuster means including an adjuster body connected to thelinkage means and a reversible screw Within said body, said meansconnected to said adjuster means and to the linkage means comprisingmeans connecting said adjuster body to said linkage means and meansslidably connecting said reversible screw and said linkage means withlimited longitudinal movement.

2. ln a brak-ing device as claimed in claim l wherein said meansslidably connecting said reversible screw and said linkage meanscomprises an extension on said screw having flat portions, a fork shapedkey including prongs mounted astride said at portions of said extension,a

blind socket accommodating said extension for sliding movement, said keybeing mounted on said socket, and a head on said extension for abuttingsaid key to limit the movement of the screw, said socket being hingedlyconneeted to said linkage means.

3. In a braking device as claimed in claim l wherein said linkage meansincludes a slide, means connected to said slide and to said linkageadjuster body for controlling the latter in accordance with movement ofthe slide, and a compression spring connected to the slide and to thelinkage means at the location where the body is connected to the linkagemeans.

4. In a braking device as claimed in claim 3 wherein said brakeactuation means is eiective to apply a force of determinable magnitudeto said braking means and the compression spring has a strength limitedto approximately 4% of the strength of the brake actuation means.

5. ln a braking device as claimed in claim 4 wherein said brakeactuation means includes a spring resisting actuation and connected tosaid linkage means to apply a force thereto just suiiicient to returnthe linkage means to a free position in which the brake means is appliedwithout force to said wheels, said compression spring being effectivewith the braking means released by the brake actuation means to causemovement of the slide with respect to the location where the adjusterbody is connected to the linkage means to activate the means connectedto the slide and to the linkage adjuster body.

6. In a braking device as claimed in claim 5 wherein said slide has anend with a hook thereon, and said means connected to said linkageadjuster body includes a pin for engaging With said hook.

7. In a braking device as claimed in claim 6 wherein said compressionspring exerts a force tending to engage said pin in said hook.

References Cited by the Examiner UNITED STATES PATENTS '923,927 6/09Anderson 118-202 2,062,497 12/36 Browall 18S-202 2,436,850 3/48 Bowen18S-198 2,699,231 Y 1/55 Dorey 18S-198 ARTHUR L. LA POINT, PrimaryExaminer.

DUANE A. REGER, JOSEPH GOLDBERG, Examiners.

1. IN A BRAKING DEVICE FOR A VEHICLE HAVING WHEELS, THE PROVISION OFBRAKING MEANS FOR BEING APPLIED AGAINST SAID WHEELS, BRAKE ACTUATIONMEANS FOR OPERATING SAID BRAKING MEANS AND HAVING EXTENDED AND RETRACTEDPOSITIONS FOR RESPECTIVELY APPLYING THE BRAKING MEANS AGAINST THE WHEELSAND RELEASING THE BRAKING MEANS, LINKAGE MEANS BETWEEN SAID BRAKEACTUATION MEANS AND SAID BRAKING MEANS AND HAVING A FULLY RELEASEDRELAXED POSITION IN WHICH THE BRAKING MEANS IS SPACED FROM THE WHEELS,LINKAGE ADJUSTER MEANS CONNECTED TO THE LINKAGE MEANS FOR ADJUSTING THECLEARANCE BETWEEN THE BRAKING MEANS AND THE WHEELS DURING OPERATION WHENTHE LINKAGE MEANS IS IN A RELAXED POSITION AND THE BRAKING MEANS IS JUSTIN CONTACT WITH THE WHEELS AND MEANS CONNECTED TO SAID ADJUSTER MEANSAND THE LINKAGE MEANS FOR PROVIDING LOST MOTION BETWEEN SAID ADJUSTERMEANS AND THE LINKAGE MEANS TO ENABLE THE LINKAGE MEANS TO REMAIN INRELAXED POSITION AS THE LINKAGE MEANS MOVES TO THE FULLY RELEASEDPOSITION IN WHICH THE BRAKING MEANS IS PROPERLY SPACED FROM THE WHEELS,SAID LINKAGE ADJUSTER MEANS INCLUDING AN ADJUSTER BODY CONNECTED TO THELINKAGE MEANS AND A REVERSIBLE SCREW WITHIN SAID BODY, SAID MEANSCONNECTED TO SAID ADJUSTER MEANS AND TO THE LINKAGE MEANS COMPRISINGMEANS CONNECTING SAID ADJUSTER BODY TO SAID LINKAGE MEANS AND MEANSSLIDABLY CONNECTING SAID REVERSIBLE SCREW AND SAID LINKAGE MEANS WITHLIMITED LONGITUDINAL MOVEMENT.